How it got its name ? #1

There i was walking around the rig on the heli deck enjoying the sunset. Then i heard a guy shouting and pointing out something at the sea. Out of curiosity (... often kills the cat..) , i went towards him and asked him

" Whats up , mate ?"

He pointed out and said " Holy  Fuck  Fudge !!  Thats one big sperm out there !! " .

I was wondering what sperm is out there.... then i realized is a sperm whale...

-_- |||

I wonder why they call it Sperm Whale ? So i Google it..

Apparently i am not the only who is curious of how it got its name.

Then i found out.

400 gallons ? .... Well , no more questions asked....